<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT    MIT License
 * @link    http://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Calendar Class
 *
 * This class enables the creation of calendars
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @category    Libraries
 * @author        EllisLab Dev Team
 * @link        http://codeigniter.com/user_guide/libraries/calendar.html
 */
class CI_Calendar {

    /**
     * Calendar layout template
     *
     * @var mixed
     */
    public $template = '';

    /**
     * Replacements array for template
     *
     * @var array
     */
    public $replacements = array();

    /**
     * Day of the week to start the calendar on
     *
     * @var string
     */
    public $start_day = 'sunday';

    /**
     * How to display months
     *
     * @var string
     */
    public $month_type = 'long';

    /**
     * How to display names of days
     *
     * @var string
     */
    public $day_type = 'abr';

    /**
     * Whether to show next/prev month links
     *
     * @var bool
     */
    public $show_next_prev = FALSE;

    /**
     * Url base to use for next/prev month links
     *
     * @var bool
     */
    public $next_prev_url = '';

    /**
     * Show days of other months
     *
     * @var bool
     */
    public $show_other_days = FALSE;

    // --------------------------------------------------------------------

    /**
     * CI Singleton
     *
     * @var object
     */
    protected $CI;

    // --------------------------------------------------------------------

    /**
     * Class constructor
     *
     * Loads the calendar language file and sets the default time reference.
     *
     * @uses    CI_Lang::$is_loaded
     *
     * @param    array    $config    Calendar options
     * @return    void
     */
    public function __construct($config = array())
    {
        $this->CI =& get_instance();
        $this->CI->lang->load('calendar');

        empty($config) OR $this->initialize($config);

        log_message('info', 'Calendar Class Initialized');
    }

    // --------------------------------------------------------------------

    /**
     * Initialize the user preferences
     *
     * Accepts an associative array as input, containing display preferences
     *
     * @param    array    config preferences
     * @return    CI_Calendar
     */
    public function initialize($config = array())
    {
        foreach ($config as $key => $val)
        {
            if (isset($this->$key))
            {
                $this->$key = $val;
            }
        }

        // Set the next_prev_url to the controller if required but not defined
        if ($this->show_next_prev === TRUE && empty($this->next_prev_url))
        {
            $this->next_prev_url = $this->CI->config->site_url($this->CI->router->class.'/'.$this->CI->router->method);
        }

        return $this;
    }

    // --------------------------------------------------------------------

    /**
     * Generate the calendar
     *
     * @param    int    the year
     * @param    int    the month
     * @param    array    the data to be shown in the calendar cells
     * @return    string
     */
    public function generate($year = '', $month = '', $data = array())
    {
        $local_time = time();

        // Set and validate the supplied month/year
        if (empty($year))
        {
            $year = date('Y', $local_time);
        }
        elseif (strlen($year) === 1)
        {
            $year = '200'.$year;
        }
        elseif (strlen($year) === 2)
        {
            $year = '20'.$year;
        }

        if (empty($month))
        {
            $month = date('m', $local_time);
        }
        elseif (strlen($month) === 1)
        {
            $month = '0'.$month;
        }

        $adjusted_date = $this->adjust_date($month, $year);

        $month    = $adjusted_date['month'];
        $year    = $adjusted_date['year'];

        // Determine the total days in the month
        $total_days = $this->get_total_days($month, $year);

        // Set the starting day of the week
        $start_days    = array('sunday' => 0, 'monday' => 1, 'tuesday' => 2, 'wednesday' => 3, 'thursday' => 4, 'friday' => 5, 'saturday' => 6);
        $start_day    = isset($start_days[$this->start_day]) ? $start_days[$this->start_day] : 0;

        // Set the starting day number
        $local_date = mktime(12, 0, 0, $month, 1, $year);
        $date = getdate($local_date);
        $day  = $start_day + 1 - $date['wday'];

        while ($day > 1)
        {
            $day -= 7;
        }

        // Set the current month/year/day
        // We use this to determine the "today" date
        $cur_year    = date('Y', $local_time);
        $cur_month    = date('m', $local_time);
        $cur_day    = date('j', $local_time);

        $is_current_month = ($cur_year == $year && $cur_month == $month);

        // Generate the template data array
        $this->parse_template();

        // Begin building the calendar output
        $out = $this->replacements['table_open']."\n\n".$this->replacements['heading_row_start']."\n";

        // "previous" month link
        if ($this->show_next_prev === TRUE)
        {
            // Add a trailing slash to the URL if needed
            $this->next_prev_url = preg_replace('/(.+?)\/*$/', '\\1/', $this->next_prev_url);

            $adjusted_date = $this->adjust_date($month - 1, $year);
            $out .= str_replace('{previous_url}', $this->next_prev_url.$adjusted_date['year'].'/'.$adjusted_date['month'], $this->replacements['heading_previous_cell'])."\n";
        }

        // Heading containing the month/year
        $colspan = ($this->show_next_prev === TRUE) ? 5 : 7;

        $this->replacements['heading_title_cell'] = str_replace('{colspan}', $colspan,
                                str_replace('{heading}', $this->get_month_name($month).'&nbsp;'.$year, $this->replacements['heading_title_cell']));

        $out .= $this->replacements['heading_title_cell']."\n";

        // "next" month link
        if ($this->show_next_prev === TRUE)
        {
            $adjusted_date = $this->adjust_date($month + 1, $year);
            $out .= str_replace('{next_url}', $this->next_prev_url.$adjusted_date['year'].'/'.$adjusted_date['month'], $this->replacements['heading_next_cell']);
        }

        $out .= "\n".$this->replacements['heading_row_end']."\n\n"
            // Write the cells containing the days of the week
            .$this->replacements['week_row_start']."\n";

        $day_names = $this->get_day_names();

        for ($i = 0; $i < 7; $i ++)
        {
            $out .= str_replace('{week_day}', $day_names[($start_day + $i) %7], $this->replacements['week_day_cell']);
        }

        $out .= "\n".$this->replacements['week_row_end']."\n";

        // Build the main body of the calendar
        while ($day <= $total_days)
        {
            $out .= "\n".$this->replacements['cal_row_start']."\n";

            for ($i = 0; $i < 7; $i++)
            {
                if ($day > 0 && $day <= $total_days)
                {
                    $out .= ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_start_today'] : $this->replacements['cal_cell_start'];

                    if (isset($data[$day]))
                    {
                        // Cells with content
                        $temp = ($is_current_month === TRUE && $day == $cur_day) ?
                                $this->replacements['cal_cell_content_today'] : $this->replacements['cal_cell_content'];
                        $out .= str_replace(array('{content}', '{day}'), array($data[$day], $day), $temp);
                    }
                    else
                    {
                        // Cells with no content
                        $temp = ($is_current_month === TRUE && $day == $cur_day) ?
                                $this->replacements['cal_cell_no_content_today'] : $this->replacements['cal_cell_no_content'];
                        $out .= str_replace('{day}', $day, $temp);
                    }

                    $out .= ($is_current_month === TRUE && $day == $cur_day) ? $this->replacements['cal_cell_end_today'] : $this->replacements['cal_cell_end'];
                }
                elseif ($this->show_other_days === TRUE)
                {
                    $out .= $this->replacements['cal_cell_start_other'];

                    if ($day <= 0)
                    {
                        // Day of previous month
                        $prev_month = $this->adjust_date($month - 1, $year);
                        $prev_month_days = $this->get_total_days($prev_month['month'], $prev_month['year']);
                        $out .= str_replace('{day}', $prev_month_days + $day, $this->replacements['cal_cell_other']);
                    }
                    else
                    {
                        // Day of next month
                        $out .= str_replace('{day}', $day - $total_days, $this->replacements['cal_cell_other']);
                    }

                    $out .= $this->replacements['cal_cell_end_other'];
                }
                else
                {
                    // Blank cells
                    $out .= $this->replacements['cal_cell_start'].$this->replacements['cal_cell_blank'].$this->replacements['cal_cell_end'];
                }

                $day++;
            }

            $out .= "\n".$this->replacements['cal_row_end']."\n";
        }

        return $out .= "\n".$this->replacements['table_close'];
    }

    // --------------------------------------------------------------------

    /**
     * Get Month Name
     *
     * Generates a textual month name based on the numeric
     * month provided.
     *
     * @param    int    the month
     * @return    string
     */
    public function get_month_name($month)
    {
        if ($this->month_type === 'short')
        {
            $month_names = array('01' => 'cal_jan', '02' => 'cal_feb', '03' => 'cal_mar', '04' => 'cal_apr', '05' => 'cal_may', '06' => 'cal_jun', '07' => 'cal_jul', '08' => 'cal_aug', '09' => 'cal_sep', '10' => 'cal_oct', '11' => 'cal_nov', '12' => 'cal_dec');
        }
        else
        {
            $month_names = array('01' => 'cal_january', '02' => 'cal_february', '03' => 'cal_march', '04' => 'cal_april', '05' => 'cal_mayl', '06' => 'cal_june', '07' => 'cal_july', '08' => 'cal_august', '09' => 'cal_september', '10' => 'cal_october', '11' => 'cal_november', '12' => 'cal_december');
        }

        return ($this->CI->lang->line($month_names[$month]) === FALSE)
            ? ucfirst(substr($month_names[$month], 4))
            : $this->CI->lang->line($month_names[$month]);
    }

    // --------------------------------------------------------------------

    /**
     * Get Day Names
     *
     * Returns an array of day names (Sunday, Monday, etc.) based
     * on the type. Options: long, short, abr
     *
     * @param    string
     * @return    array
     */
    public function get_day_names($day_type = '')
    {
        if ($day_type !== '')
        {
            $this->day_type = $day_type;
        }

        if ($this->day_type === 'long')
        {
            $day_names = array('sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday');
        }
        elseif ($this->day_type === 'short')
        {
            $day_names = array('sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat');
        }
        else
        {
            $day_names = array('su', 'mo', 'tu', 'we', 'th', 'fr', 'sa');
        }

        $days = array();
        for ($i = 0, $c = count($day_names); $i < $c; $i++)
        {
            $days[] = ($this->CI->lang->line('cal_'.$day_names[$i]) === FALSE) ? ucfirst($day_names[$i]) : $this->CI->lang->line('cal_'.$day_names[$i]);
        }

        return $days;
    }

    // --------------------------------------------------------------------

    /**
     * Adjust Date
     *
     * This function makes sure that we have a valid month/year.
     * For example, if you submit 13 as the month, the year will
     * increment and the month will become January.
     *
     * @param    int    the month
     * @param    int    the year
     * @return    array
     */
    public function adjust_date($month, $year)
    {
        $date = array();

        $date['month']    = $month;
        $date['year']    = $year;

        while ($date['month'] > 12)
        {
            $date['month'] -= 12;
            $date['year']++;
        }

        while ($date['month'] <= 0)
        {
            $date['month'] += 12;
            $date['year']--;
        }

        if (strlen($date['month']) === 1)
        {
            $date['month'] = '0'.$date['month'];
        }

        return $date;
    }

    // --------------------------------------------------------------------

    /**
     * Total days in a given month
     *
     * @param    int    the month
     * @param    int    the year
     * @return    int
     */
    public function get_total_days($month, $year)
    {
        $this->CI->load->helper('date');
        return days_in_month($month, $year);
    }

    // --------------------------------------------------------------------

    /**
     * Set Default Template Data
     *
     * This is used in the event that the user has not created their own template
     *
     * @return    array
     */
    public function default_template()
    {
        return array(
            'table_open'                => '<table border="0" cellpadding="4" cellspacing="0">',
            'heading_row_start'            => '<tr>',
            'heading_previous_cell'        => '<th><a href="{previous_url}">&lt;&lt;</a></th>',
            'heading_title_cell'        => '<th colspan="{colspan}">{heading}</th>',
            'heading_next_cell'            => '<th><a href="{next_url}">&gt;&gt;</a></th>',
            'heading_row_end'            => '</tr>',
            'week_row_start'            => '<tr>',
            'week_day_cell'                => '<td>{week_day}</td>',
            'week_row_end'                => '</tr>',
            'cal_row_start'                => '<tr>',
            'cal_cell_start'            => '<td>',
            'cal_cell_start_today'        => '<td>',
            'cal_cell_start_other'        => '<td style="color: #666;">',
            'cal_cell_content'            => '<a href="{content}">{day}</a>',
            'cal_cell_content_today'    => '<a href="{content}"><strong>{day}</strong></a>',
            'cal_cell_no_content'        => '{day}',
            'cal_cell_no_content_today'    => '<strong>{day}</strong>',
            'cal_cell_blank'            => '&nbsp;',
            'cal_cell_other'            => '{day}',
            'cal_cell_end'                => '</td>',
            'cal_cell_end_today'        => '</td>',
            'cal_cell_end_other'        => '</td>',
            'cal_row_end'                => '</tr>',
            'table_close'                => '</table>'
        );
    }

    // --------------------------------------------------------------------

    /**
     * Parse Template
     *
     * Harvests the data within the template {pseudo-variables}
     * used to display the calendar
     *
     * @return    CI_Calendar
     */
    public function parse_template()
    {
        $this->replacements = $this->default_template();

        if (empty($this->template))
        {
            return $this;
        }

        if (is_string($this->template))
        {
            $today = array('cal_cell_start_today', 'cal_cell_content_today', 'cal_cell_no_content_today', 'cal_cell_end_today');

            foreach (array('table_open', 'table_close', 'heading_row_start', 'heading_previous_cell', 'heading_title_cell', 'heading_next_cell', 'heading_row_end', 'week_row_start', 'week_day_cell', 'week_row_end', 'cal_row_start', 'cal_cell_start', 'cal_cell_content', 'cal_cell_no_content', 'cal_cell_blank', 'cal_cell_end', 'cal_row_end', 'cal_cell_start_today', 'cal_cell_content_today', 'cal_cell_no_content_today', 'cal_cell_end_today', 'cal_cell_start_other', 'cal_cell_other', 'cal_cell_end_other') as $val)
            {
                if (preg_match('/\{'.$val.'\}(.*?)\{\/'.$val.'\}/si', $this->template, $match))
                {
                    $this->replacements[$val] = $match[1];
                }
                elseif (in_array($val, $today, TRUE))
                {
                    $this->replacements[$val] = $this->replacements[substr($val, 0, -6)];
                }
            }
        }
        elseif (is_array($this->template))
        {
            $this->replacements = array_merge($this->replacements, $this->template);
        }

        return $this;
    }

}
